Stoichiometric ZnSe nanowires have been grown by pulsed-laser deposition on GaAs (100) substrates coated with gold layers. The gold layer plays a key role as catalyst in the deposition of ZnSe nanowires. The thickness of the gold film greatly affected the density of the ZnSe nanowires synthesized on the substrate. No ZnSe nanowires were synthesized on the bare GaAs (100) substrate. The microstructures and the chemical compositions of the as-synthesized nanowires were investigated by scanning electron microscopy, x-ray diffraction, and Raman spectroscopy. The results reveal that the as-grown thin films consist of ZnSe nanowires with diameters ranging from 20 to 40 nm, and the nanowires appear to be randomly oriented on the Au-coated substrate. The as-grown nanowires were also observed to be elongated along different crystallographic directions. (C) 2007 American Vacuum Society.